From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762212AbbAaBeV (ORCPT ); Fri, 30 Jan 2015 20:34:21 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:4029 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752290AbbAaBeU (ORCPT ); Fri, 30 Jan 2015 20:34:20 -0500 Message-ID: <54CC3105.1050200@huawei.com> Date: Sat, 31 Jan 2015 09:33:57 +0800 From: "Yun Wu (Abel)" User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:11.0) Gecko/20120327 Thunderbird/11.0.1 MIME-Version: 1.0 To: Marc Zyngier CC: "tglx@linutronix.de" , "jason@lakedaemon.net" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 3/5] irqchip: gicv3-its: use 64KB page as default granule References: <1422604009-9248-1-git-send-email-wuyun.wu@huawei.com> <1422604009-9248-4-git-send-email-wuyun.wu@huawei.com> <54CBD8FD.1030908@arm.com> In-Reply-To: <54CBD8FD.1030908@arm.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.24.136] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020206.54CC311A.0125,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 1575d42e80d8b885ca42dcb81df32dcf Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/1/31 3:18, Marc Zyngier wrote: > On 30/01/15 07:46, Yun Wu wrote: >> The field of page size in register GITS_BASERn might be read-only >> if an implementation only supports a single, fixed page size. But >> currently the ITS driver will throw out an error when PAGE_SIZE >> is less than the minimum size supported by an ITS. So addressing >> this problem by using 64KB pages as default granule for all the >> ITS base tables. > > Do you actually know of an implementation with such a behaviour? Yes, Hisilicon implemented a fixed page size of 16KB. > >> Signed-off-by: Yun Wu >> --- >> drivers/irqchip/irq-gic-v3-its.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c >> index 2a08d85..430bc92 100644 >> --- a/drivers/irqchip/irq-gic-v3-its.c >> +++ b/drivers/irqchip/irq-gic-v3-its.c >> @@ -801,7 +801,7 @@ static int its_alloc_tables(struct its_node *its) >> int err; >> int i; >> int size; >> - int psz = PAGE_SIZE; >> + int psz = SZ_64K; >> u64 shr = GITS_BASER_InnerShareable; >> >> for (i = 0; i < GITS_BASER_NR_REGS; i++) { > > Assuming such an implementation exists, you'll have to rebase this on > top of the patch I mentioned in my reply to patch #1. > OK, I will. Thanks, Abel